Figure 5.

Anthrax LT-induced c-Jun degradation is not due to destabilization of Fra-1. Cells were extracted with SDS sample buffer after treatment as indicated below. The expression levels of the indicated proteins in the cells lysates were assessed by Western blotting. A, Hepa1c1c7 cells were left untreated (M) or treated with U0126 for 1 h. B, Hepa1c1c7 cells were left untreated or treated with LT for 1, 2, and 4 h. C, Hepa1c1c7 cells expressing GFP (Control), HA-Fra-1/GFP, or HA-Fra-12D/GFP were left untreated or treated with LT for 4 h. D, Hepa1c1c7 cells were transfected with control siRNA or Fra-1–specific siRNA. Three days after transfection, cells were left untreated or treated with LT for 2 and 4 h or U0126 for 1 h. β-Actin was used as a loading control. Data shown are representative of at least two independent experiments. The intensities of protein bands were quantified using the Image Studio software of the Odyssey system and normalized by the amounts of β-actin; relative amounts are shown below each lane.